1. Field of the Invention
The invention relates to a cassette loading mechanism for loading a cassette and, more particularly, to a cassette loading mechanism of a front loading system.
2. Description of the Prior Art
Hitherto, a front loading system has been known as one of cassette loading mechanisms of a recording and reproducing apparatus using a tape-shaped recording medium. As one of the standards using the tape-shaped recording medium, there is what is called an 8 mm standard using a magnetic tape having a width of 8 mm. As disclosed in U.S. Pat. No. 4,631,618 or the like, the magnetic tape of the 8 mm standard is enclosed in a tape cassette. To protect the magnetic tape, a lid body comprising a front lid and a back lid for covering the magnetic tape from the upper and lower directions when the tape cassette is not used is provided for the tape cassette.
A case of applying the cassette loading mechanism of the front loading system to the tape cassette of the 8 mm standard will now be considered.
Generally, in the cassette loading mechanism of the front loading system, a tape cassette is loaded into a cassette holder, the cassette holder is first moved in the horizontal direction, and the cassette holder is subsequently moved downward, thereby loading the cassette holder. Both of the front lid and the back lid have to be opened for a period of time until the end of the loading. Further, the back lid is moved fairly upward for the cassette main body from a state in which the opening of the back lid is started. Therefore, the upper surface of a casing of the recording and reproducing apparatus cannot help being set to an upper position than the highest point in the moving loci of the front lid and back lid. In other words, a height of recording and reproducing apparatus cannot be suppressed to a low height.
As one of the methods of solving the above drawback, a method disclosed in JP-A-4-14661 has already been proposed. According to the loading mechanism disclosed in JP-A-4-14661, the rear side in the inserting direction of a tape cassette is set to a state in which it is lower than the front side, a tape cassette is inserted toward the rear side of the recording and reproducing apparatus, and the tape cassette is subsequently descended downward, thereby finishing the loading. To realize such an operation, the above loading mechanism needs: a loading arm for depressing downward a pin on the rear side in the inserting direction between a pair of pins provided in the front and rear directions of a cassette holder so as to be away from each other; a slider for preventing that the pin on the front side of the cassette holder drops downward; and a gear train for coupling an output axis of a motor and the loading arm in order to drive the loading arm. There are, consequently, problems such that the structure is complicated and the dimension in the width direction increases.
The recording and reproducing apparatus using a tape-shaped recording medium (hereinafter, such an apparatus is referred to as a cassette tape recorder) is also used not only for a video signal and audio signals but also as a data streamer as an auxiliary memory device or the like of a computer.
A disk drive apparatus is well known as a data streamer. Disks having sizes of 5 inches and 3.5 inches are used. To make the assembling operation into the computer easy, such a disk drive apparatus generally has standard external dimensions. For example, the standard size of a thin disk drive apparatus of 5.25 inches called a half height has dimensions such that a width (W) is equal to 146 mm and a height (H) is equal to 41.25 mm. The standard size of a disk drive apparatus of 3.5 inches called a standard height has dimensions such that a width (W) is equal to 101.6 mm and a height (H) is equal to 41.25 mm and a depth (D) is equal to 150 mm.
Therefore, when the cassette tape recorder is used as a data streamer, it is desirable to have the same size as the external shape of the existing disk drive apparatus. In case of constructing the cassette tape recorder as a drive apparatus, the drive apparatus has a construction such that a cassette loading mechanism, a tape loading mechanism to wrap a tape around a tape guide drum, a reel base plate drive motor, and the like are enclosed in a common casing. It is desirable that the size of casing is the same as the size of the existing disk drive apparatus.
As for a data streamer, it is preferable to use the front loading system as a tape loading mechanism from a viewpoint of the limitation of the size mentioned above when using the cassette tape recorder. However, even with respect to the cassette loading mechanism of the front loading system, complicated operations such that the cassette inserted from the front side is led into the rear side and is further moved downward and is loaded at a predetermined cassette loading position have to be executed. A mechanism for such a purpose is complicated. It is, consequently, difficult to construct a data streamer of the same size as the standard size of the disk drive apparatus of 3.5 inches with regard to the width and height.
Specifically speaking, when considering a case of using the cassette of a tape width of 8 mm as a data streamer, the standard of the lateral width of the cassette is equal to 95.+-.0.2 mm (maximum, 95.2 mm). On the other hand, the lateral width of the existing disk drive apparatus of 3.5 inches is equal to 101.6 mm. Therefore, with respect to the lateral width, there is only an allowance of 6.4 mm (3.2 mm on one side).
Since a standard height of the above-mentioned disk drive apparatus is equal to 41.25 mm, when considering of a height of reel driving section, it is necessary to set a length from the upper surface of the casing to the lower surface when the cassette is loaded to a value of 35 mm or less.
In consideration of a thickness (for instance, 0.5 mm) of the casing and a thickness (for example, 0.8 mm) of the cassette holder, with respect to the lateral width, it is necessary to construct the cassette loading mechanism so as to have a width of 1.9 mm or less. As for the height, when also considering a mounting space of an electric board, it is necessary to construct the cassette loading mechanism so as to have a height of, for example, 29.1 mm or less.